Article

Activation of apoptosis in vivo by a hydrocarbon-stapled BH3 helix.

Howard Hughes Medical Institute, Department of Pediatric Hematology/Oncology and Children's Hospital Boston, Massachusetts, USA.
Science (Impact Factor: 31.2). 10/2004; 305(5689):1466-70. DOI: 10.1126/science.1099191
Source: PubMed

ABSTRACT BCL-2 family proteins constitute a critical control point for the regulation of apoptosis. Protein interaction between BCL-2 members is a prominent mechanism of control and is mediated through the amphipathic alpha-helical BH3 segment, an essential death domain. We used a chemical strategy, termed hydrocarbon stapling, to generate BH3 peptides with improved pharmacologic properties. The stapled peptides, called "stabilized alpha-helix of BCL-2 domains" (SAHBs), proved to be helical, protease-resistant, and cell-permeable molecules that bound with increased affinity to multidomain BCL-2 member pockets. A SAHB of the BH3 domain from the BID protein specifically activated the apoptotic pathway to kill leukemia cells. In addition, SAHB effectively inhibited the growth of human leukemia xenografts in vivo. Hydrocarbon stapling of native peptides may provide a useful strategy for experimental and therapeutic modulation of protein-protein interactions in many signaling pathways.

0 Bookmarks
 · 
95 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Helix-constrained polypeptides have attracted great interest for modulating protein-protein interactions (PPI). It is not known which are the most effective helix-inducing strategies for designing PPI agonists/antagonists. Cyclization linkers (X1 -X5 ) were compared here, using circular dichroism and 2D NMR spectroscopy, for α-helix induction in simple model pentapeptides, Ac-cyclo(1,5)-[X1 -Ala-Ala-Ala-X5 ]-NH2 , in water. In this very stringent test of helix induction, a Lys1→Asp5 lactam linker conferred greatest α-helicity, hydrocarbon and triazole linkers induced a mix of α- and 310 -helicity, while thio- and dithioether linkers produced less helicity. The lactam-linked cyclic pentapeptide was also the most effective α-helix nucleator attached to a 13-residue model peptide.
    Angewandte Chemie International Edition 05/2014; · 11.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BCL-W is a member of the BCL-2 family of anti-apoptotic proteins. A key event in the regulation of apoptosis is the heterodimerization between anti-apoptotic and pro-apoptotic family members, which involves a conserved surface-exposed groove on the anti-apoptotic proteins. Crystal structures of the ligand binding-competent conformation exist for all anti-apoptotic family members, with the exception of BCL-W, due to the flexibility of the BCL-W groove region. Existing structures had suggested major deviations of the BCL-W groove region from the otherwise structurally highly related remaining anti-apoptotic family members. To capture its ligand binding-competent conformation by counteracting the conformational flexibility of the BCL-W groove, we had selected high-affinity groove-binding designed ankyrin repeat proteins (DARPins) using ribosome-display. We now determined two high-resolution crystal structures of human BCL-W in complex with different DARPins at a resolution of 1.5 and 1.85Å, in which the structure of BCL-W is virtually identical, and in both structures BCL-W adopts a conformation extremely similar to the ligand-free conformation of its closest relative BCL-XL. However, distinct differences to all previous BCL-W structures are evident, notably in the ligand-binding region. We provide the first structural explanation for the conformational flexibility of the BCL-W groove region in comparison to other BCL-2 family members. Due to the importance of the anti-apoptotic BCL-2 family as drug targets, the presented crystal structure of ligand binding-competent BCL-W may serve as a valuable basis for structure-based drug design in the future and provides a missing piece for the structural characterization of this protein family.
    Journal of Molecular Biology 04/2014; · 3.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Respiratory syncytial virus (RSV) infection accounts for approximately 64 million cases of respiratory disease and 200,000 deaths worldwide each year, yet no broadly effective prophylactic or treatment regimen is available. RSV deploys paired, self-associating, heptad repeat domains of its fusion protein, RSV-F, to form a fusogenic 6-helix bundle that enables the virus to penetrate the host cell membrane. Here, we developed hydrocarbon double-stapled RSV fusion peptides that exhibit stabilized α-helical structure and striking proteolytic resistance. Pretreatment with double-stapled RSV peptides that specifically bound to the RSV fusion bundle inhibited infection by both laboratory and clinical RSV isolates in cells and murine infection models. Intranasal delivery of a lead double-stapled RSV peptide effectively prevented viral infection of the nares. A chitosan-based nanoparticle preparation markedly enhanced pulmonary delivery, further preventing progression of RSV infection to the lung. Thus, our results provide a strategy for inhibiting RSV infection by mucosal and endotracheal delivery of double-stapled RSV fusion peptides.
    The Journal of clinical investigation 04/2014; · 15.39 Impact Factor

Full-text (2 Sources)

View
38 Downloads
Available from
May 31, 2014

Renee D. Wright-Michaud